JPS59169890A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enhance stability of an image part and a ground part, by a method wherein a thiourea compound having an allyl group is used as a color developer, in a thermal recording material using a leuco dye. CONSTITUTION:A thermal color forming layer is provided on a base by using 5-30wt% of a conventional leuco dye such as a triphenylmethane base leuco dye or a fluoran base leuco dye, about 40-80wt% of an allyl group containing thiourea compound of the formula (wherein each of R1-R3 is H or an organic group) as a color developer and 2-20wt% of a conventional binder such as PVA or starch together with a filler, a surface active agent, a heat-fusible substance or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer.

[Prior art]

Thermosensitive recording materials generally have a thermosensitive coloring layer containing a thermochromic composition as a main component on a support such as synthetic paper or plastic film, and can be heated using a heat roller, heat vent, laser beam, etc. A colored image can be obtained by heating. Compared to other recording materials, this type of recording material does not require complicated processing such as development and fixing, can produce records in a short time using relatively simple equipment, and generates less noise and pollutes the environment. , Books due to its advantages such as low cost.

In addition to being used for copying documents, it is also widely used as a recording material in a wide variety of applications, including electronic computers, facsimile machines, ticket vending machines, labels, and recorders.

Thermochromic compositions used in such heat-sensitive recording materials generally consist of a color former and a color developer that causes the color former to develop color when heated. As the color former, for example, a composition having a lactone, lactam or spiropyran ring Colorless or light-colored leuco dyes are used, and various acidic substances such as organic acids and phenolic substances are used as color developers. A recording material that combines a color former and a color developer has the advantage that the resulting image has a particularly clear color tone, a high background whiteness, and a dye image (dye image) that has excellent light fastness. have,
Widely used.

However, with conventional heat-sensitive recording materials, if they come into contact with organic solvents or oils after image formation, the image area or background area (
Since the non-image area (non-image area) is discolored or colored, and the image becomes unclear, it has been difficult to use this method, especially in fields where reliability of a single image is required.

〔the purpose〕

An object of the present invention is to provide a heat-sensitive recording material that overcomes the problems of the prior art described above and has good stability in the image area and the background area.

〔composition〕

According to the present invention, there is provided a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer, characterized in that a thiourea compound having an allyl group is used as the color developer. provided.

The allyl group-containing thiourea compound used as a color developer in the present invention is usually represented by the following general formula (wherein 11R=2 and FL3 represent hydrogen or an organic group). In this case, the organic group includes an alkyl group, an allyl group, an alkoxy group, a hydroxyalkyl group, and various aromatic groups. Aromatic groups include aryl groups, aryloxy groups, substituted aryl or aryloxy groups. More specifically, alkyl groups include those having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, octyl, etc., and alkoxy groups include those having 1 to 10 carbon atoms, such as methoxy, ethoxy, butoxy. , octyloxy group, etc. The hydroxyalkyl group includes those having 1 to 10 carbon atoms, such as hydroxymethyl, hydroxyethyl,
Aryl groups such as hydroxybutyl and hydroxyethyl include phenyl groups, tolyl groups, naphthyl groups, etc.
Examples of the substituted aryl group include hydroxyphenyl group, methoxyphenyl group, and halogen-substituted phenyl group; examples of the aryloxy group or substituted aryloxy group include phenoxy group, hydroxyphenoxy group, and hydroxyl group; Examples include ethyl group, methoxyphenoxy group, naphthyloxy group, and the like. Specific examples of allyl group-containing thiourea compounds include allyl thiourea,
Diallylthiourea L I-allyl-3-β-hydroxyethyl 2-thiourea, 1-allyl-3-n-octyl-
2-thiourea, 1-allyl-3-'n-hexyl-2-
Thiourea, ■-aryl-3-phenyl-2-thiourea,
l-allyl-3-m-chlorobenzene-2-thiourea,
■-Allyl-3-α-naphthyl-2-thiourea and the like. The color developer is used in an appropriate amount to cause the leuco dye used as a color former to develop color when heated.

The leuco dyes used in the present invention can be applied singly or in combination of two or more types, but such leuco dyes include:
Any dye that has been applied to this type of heat-sensitive material may be used, and for example, leuco compounds of dyes such as triphenylmethane, fluoran, phenothiazine, auramine, and spiropyran dyes are preferably used. Specific examples of such leuco dyes include those shown below.

3,3-bis(p-)methylaminophenyl)-phthalate
Lido, 5-3,3-his(p-1 methylaminophenyl)-6-,
) Methylaminophthalyl r (also known as crystalline iolet lactone, 3,3-his(p-dimethylaminophenyl) = 6-
Dibutylaminophenyl, 3.3-bis(p-)methylaminophenyl)=6-chlorphthalide, 3.3-1:"(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluoran , 3-dimethylamino-5,7-,) methylfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamine-7-methylfluoran, 3-diethylamine-7,8-benzfluoran, 3- Diethylamino-6-methyl-7-chlorofluorane, 3-(NP-tolyl-N-ethylamino)-6- 6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7- Anilinofluorane, 2-(N-(3'-triyolmethylphenyl)amino)-6-dinithylaminofluorane, 2-(3,6
-bis(diethylamine)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethyl7mi/-7-(o -Chloranilino)fluoran, 3-dibutylamino-7-(o-chlora=IJ))
Fluoran, 3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6
-Methyl-7-anilinofluorane, 3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluorane, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylosbilane, 6'-bromo-3'-methoxy-benzoindolino-pyrylospirane, 3-(2 '-HyProxy4'-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)
Phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl) -3-(2'-methoxy-5'-nitrophenyl)phthalide, 3-(2'-hyproxy4'-diethylaminophenyl) - 3-(2'-methoxy-5'-methylphenyl)phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-hyproxy4'-chloro-51-
methylphenyl)phtali P1 3-morpholino-7-(N--j robiroottrifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-(,)-p-chlorophenyl)methylaminofluorane, 3-1: r-f-ruamino-5-chloro-7-( α-phenylethylamino)fluoran, 3-(N-ethyl-p-)luidino)-7-(α-phenylethylamino)fluoran, 3-diethylamine-
7-(o-methoxycarbonylphenylamino)fluoran, 3-,)ethylamino-5-methyl-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-piveridinofluoran 9-, 2-chloro-3-(N-methyltoluidino)-7-(p
-n-butylanilino)fluoran, 3-(N-benzyl-cyclohexylamino)-5,6-henzo7-
α-Naphthylamino=4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzofluorane etc. These may be used alone or in combination of two or more.

In the present invention, in order to bind and support the leuco dye and color developer on the support, various commonly used binders can be used as appropriate, such as polyvinyl alcohol, starch and its derivatives, methoxycellulose, Cellulose derivatives such as Poxyethylcellulose, calxoxymethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyro IJ)%
Acrylic acid amide/acrylic acid ester copolymer,
Acrylic acid amide/acrylic ester/methacrylic acid ternary copolymer, styrene/maleic anhydride 10-coalkali salt, isobutylene/maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein, etc. In addition to water-soluble polymers, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic ester, vinyl chloride/♂yl acetate copolymer, polybutyl methacrylate,
Latex such as ethylene/vinyl acetate copolymer, styrene/butadiene/acrylic copolymer, etc. can be used.

In addition, in the present invention, in addition to the leuco dye and color developer, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, thermofusible substances ( or lubricant), etc. can be used in combination. In this case, fillers include, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, ζlium sulfate, clay, talc, and inorganic microorganisms such as surface-treated calcium carbonate and silica. In addition to powder, urea-formalin resin, styrene/methacrylic acid copolymer,
Organic fine powder such as polystyrene resin can be mentioned, and examples of thermofusible substances include higher fatty acids or their esters, amides or metal salts, various waxes, aromatic carzene acids and amines, etc. Condensates, benzoic acid phenyl esters, higher linear glycols, dialkyl 3,4-epoxy-hexahydrophthalates, higher ketones, and other thermofusible organic compounds with melting points of about 50 to 200°C Things can be mentioned.

The heat-sensitive recording material of the present invention can have various structures, including all conventionally known structures that utilize a color-forming reaction between a leuco dye and a color developer. For example, the heat-sensitive recording material of the present invention has a structure in which a leuco dye and a color developer are supported on a support as the same coating layer or separate coating layers, or a heat-sensitive recording material in which a leuco dye is supported as a transfer layer. It can be used as a thermal transfer type heat-sensitive recording material consisting of a transfer sheet supported on a body and a receptor sheet supported on a support using a color developer as a receptor layer.

In the case of thermal transfer type thermal recording materials, the transfer sheet is
A desired colored image can be formed on the receiving layer surface of the receiving sheet by overlapping the receiving sheets so that the receiving layer is in contact with the transfer layer of the transfer sheet and thermally printing from the front or back surface of the polymerized sheet.

The heat-sensitive recording material of the present invention can be produced by, for example, applying a coating solution for forming a heat-sensitive layer containing each of the above-mentioned components onto a suitable support such as paper, synthetic paper, or plastic film, and drying it. It is used in various recording fields, especially as a heat-sensitive recording material for high-speed recording that requires high image stability. The appropriate amounts of the leuco dye, developer and binder used here are 5 to 30% by weight, 40 to 80% by weight, and 2 to 20% by weight, respectively. The amount of the heat-sensitive coloring layer to be formed is preferably about 2 to 10 g/m''.

The heat-sensitive recording material of the present invention is used in various fields, but in particular, it takes advantage of the above-mentioned excellent color image stability,
It can be advantageously used as a heat-sensitive recording type label sheet or a heat-sensitive recording type magnetic ticket paper. In the case of a heat-sensitive recording film sheet, a heat-sensitive coloring layer containing the above-mentioned fluoran compound and phenolic compound is provided on one side of the support, and a heat-sensitive coloring layer containing the above-mentioned fluoran compound and phenolic compound is provided on the other side of the support through an adhesive layer. A release mount may be provided, and in the case of magnetic ticket paper, a magnetic recording layer containing a ferromagnetic material and a binder as main components may be provided in place of the release mount.

〔effect〕

By using an allyl group as a color developer, the heat-sensitive recording material of the present invention provides a highly stable image with excellent solvent resistance and oil and fat resistance, and also has excellent stability in non-image areas.

〔Example〕

The present invention will now be explained in detail by way of examples. All of the following departments and sections are based on weight.

Example 1 [Liquid A]: 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilite fluorane 10 parts Hydroxyethyl cellulose 10% aqueous solution 10 p 14 - Water
30 parts [Liquid B]: Urea formalin resin 20 parts Zinc stearate 5. Polyvinyl alcohol 10% aqueous solution 25. Water
150 [Liquid C]
: Allylthiourea 10 parts hydroxyethyl cellulose 10% aqueous solution]-0# water
30
〃The mixtures having the above compositions were each dispersed in a Dirumil to obtain liquids A, B, and C. The dispersion was carried out so that the average particle size of liquid A was 3 μm or less, and the average particle size of liquids B and C was 5 p or less. In this way, the obtained dispersion is prepared as Solution A:
Mix B solution: C solution = 10 parts = 20 parts: 50 parts,
Furthermore, add 10 parts of an aqueous solution of polyvinyl alcohol to this.
and 10 parts of water to form a heat-sensitive coloring layer coating solution, and the dry adhesion amount was 4.0 g on high-quality paper with a basis weight of 52 g/m2.
/m2 and dried to obtain the heat-sensitive recording material of the present invention.

Example 2 A heat-sensitive recording material of the present invention was obtained in the same manner as in Example 1, except that Liquid D having the following composition was used instead of Liquid C in Example 1.

[Liquid D]: 1-Oriru 3-β-hydroxyethyl-2-thiourea 10 parts Hydroxyethylcellulose 10% aqueous solution 10p Water
30 Comparative Example 1 A comparative heat-sensitive recording material was obtained in the same manner as in Example J, except that Liquid E having the following composition was used instead of Liquid C in Example 1.

[Liquid E]: Bisphenol A, 1.0 parts hydroxyethylcellulose 10% aqueous solution 10 parts water

30 Dispersed in a Zeel mill to reduce the average particle size to 5μ or less.

The heat-sensitive recording materials of the present invention and comparative heat-sensitive recording materials obtained as described above were printed at 150°C using a commercially available thermal gradient tester, and their oil resistance and solvent resistance were tested. Image and background density were measured using Macbeth densitometer RD-514 (filter 1).
06). In addition, the oil resistance test was performed by applying a thin layer of cottonseed oil to the image area and leaving it in a constant temperature layer at 40°C for 15 hours.The alcohol resistance test was performed by applying a thin layer of cottonseed oil to the image area and leaving it in a constant temperature layer at 40℃ for 15 hours.The alcohol resistance test was performed by dropping ethyl alcohol onto the background area and determining the concentration after air drying. The changes were measured. The results are shown in Table-1.

Table 1 As can be seen from the above results, oil resistance and alcohol resistance are significantly improved by using the color developer of the present invention.

17-

Claims (1)

[Claims] (1) A heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a color developer, characterized in that a thiourea compound having an allyl group is used as the color developer.